From nobody Mon Jun 8 14:36:10 2026 Received: from mail-qt1-f202.google.com (mail-qt1-f202.google.com [209.85.160.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A7C3E28B4E1 for ; Thu, 28 May 2026 16:00:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779984010; cv=none; b=oHsjvenWQTU4+ZHR7B4j+uHUrNZdQmqMlJ8cJ8N1FEkgfwJ1OQfEDHPbz2N8Yu9kwTK6dHsRqGcsRhrcoYTF5J82kObJPrr9D5fR1VyXkgv2ORVDbsvtCzEzrQ4DNrEcfO4PEFgl17/J8pYg4Y+Blt0X+Y0t7nDVRe1J4JuosJs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779984010; c=relaxed/simple; bh=k10mRhLr6t76p4jkzZqe4TGLVfCDjV4dlalSEfzSMXc=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=UPmoLNkLKJQO8RhsRQiHNeYLkX4QOn5ejlr2PdrWOS0D51LjdYFh5LWcp63NXLJx655TtHVXMddB1SUFRV3TV6ujfsgkRfTFDUe+ADI+4+HUwndaR/JLIumlu2Ud87ktVRz100m1MoCupSvyUR4CLf+eCflfoNtsydBhXue9iL8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--xuehaohu.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=ndwdrdB/; arc=none smtp.client-ip=209.85.160.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--xuehaohu.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ndwdrdB/" Received: by mail-qt1-f202.google.com with SMTP id d75a77b69052e-516d6cf547bso139541021cf.3 for ; Thu, 28 May 2026 09:00:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1779984008; x=1780588808; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=MmPFy91yuYd+9nLUOi1wu2JWcf7o4ksos6H5oNntzCU=; b=ndwdrdB/TY/1mOUW8Y7MzpFTYlhh9Egy5wG7+8X4yga3hJdr/MyA6zKbcfnghFtfOJ JuJuK2r6tMNA6MpN5KOnfypR2tkMOXHGNpsBbTxzD5B+uGG4CwTTMMLDNDNV5RYPmF0K 9W+wo2S+Z0nnA14+Svi2WkJElb5BzrasnGgh/u9GhJR5ZxconGMyrpByJFXhe4YddqM3 55DR8AT8D6BABYU8l8/Igp1TNjGuCBcd6B7pAYYVJbTFXOjzZHzQZ8aHeKqLF89kmUP/ MPoDmYYw8/LdJnSDnVj9AeNOdQ1lsCEnVk6FWXHKdfBoo6g0GP3g07zbBcuosygh7CWX P3lQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779984008; x=1780588808; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=MmPFy91yuYd+9nLUOi1wu2JWcf7o4ksos6H5oNntzCU=; b=K2jwlCVx9SQH9PeDvpCTpM3eIiOu3wRtWewUTI0IhVeGdPXSF0u/nKsHZHkH2UsuEK 8vrC8k9h99we6yb+39q1HE4YSfKM5RqcySP8J5i5loHax2g6S9uGoIuE7L8Pnykgn34r swIdIH3eysiZYBFU/BNmirXm9lPUwGR62HsHHe71EjJXIq5lb1xsIwpsCVPuYpCKMNUv /YXho/ZjmooJu8iVHScKPFprhHqYADPv7/4fHEbry98EB4YXltiHJpQI2eBLwMZWE+aa AhLgMK1/uyHCSfYtl4XPqnw5d7z9gpDz6JlHVM/lduOY+JcVhaudkRKOlvZ/CUwuWPTv sj1Q== X-Forwarded-Encrypted: i=1; AFNElJ+10/9WvaPP0crlgwNOF3flOFS+Ax6ybz+xCa3F/wy0fXyJRMGG8DkqZwDPNXNEGRdsAE6UAoEZs3Bvx6s=@vger.kernel.org X-Gm-Message-State: AOJu0Yz6fcGaR7wz6ZT7l0YdWBDxPPCjmCnC3FpCaBH02WFCS++ZrVAC KZNbhHWS6+wClSdxx93NIPzsDsVu9/x6I0YbeZ/4XOZFbp/lQlNq/cb4a4QlrQgoixYZ4TvZs5W S+NZkZv3q6PUh X-Received: from qtxy12.prod.google.com ([2002:a05:622a:120c:b0:516:373e:a942]) (user=xuehaohu job=prod-delivery.src-stubby-dispatcher) by 2002:a05:622a:1488:b0:516:d6a4:fd69 with SMTP id d75a77b69052e-516d6a4fe46mr371616761cf.12.1779984005890; Thu, 28 May 2026 09:00:05 -0700 (PDT) Date: Thu, 28 May 2026 16:00:04 +0000 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.54.0.794.g4f17f83d09-goog Message-ID: <20260528160004.2452461-1-xuehaohu@google.com> Subject: [PATCH v3] dma-buf: Fix silent overflow for phys vec to sgt From: David Hu To: Sumit Semwal , "=?UTF-8?q?Christian=20K=C3=B6nig?=" Cc: Nicolin Chen , Leon Romanovsky , Kevin Tian , Ankit Agrawal , Jason Gunthorpe , Alex Williamson , linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org, jmoroni@google.com, praan@google.com, David Hu , stable@vger.kernel.org, iommu@lists.linux.dev Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" In case MMIO size is bigger than 4G and peer2peer DMA goes through host bridge, we trigger a code path that assigns the total linked IOVA (which is greater than 4G) to mapped_len. Previously, `mapped_len` was declared as 32-bit `unsigned int`. When accumulating `size_t` lengths, this leads to a silent wrap-around. This truncation causes truncated lengths to be passed to functions like `fill_sg_entry()`. Fix this by changing `mapped_len` to `size_t` (64-bit). While at it, fix similar potential overflow issues in `calc_sg_nents` by using `size_t` for `nents` and checking against `UINT_MAX` and using `unsigned int` for the loop iterator in `fill_sg_entry` to match. Fixes: 3aa31a8bb11e ("dma-buf: provide phys_vec to scatter-gather mapping r= outine") Cc: stable@vger.kernel.org Cc: iommu@lists.linux.dev Reviewed-by: Pranjal Shrivastava Signed-off-by: David Hu --- Changes in v3: - Removed leftover sentence fragment from the commit message. - Kept `nents =3D 0` initialization (previously stated as removed in the v2 changelog) as it is strictly required for the `+=3D` accumulation loop in `calc_sg_nents()`. Changes in v2: - Fixed 'IVOA' -> 'IOVA' typo and expanded commit message (Claude Bot). - Added Reverse Xmas tree formatting (Pranjal). - Folded in extra bounds checking for calc_sg_nents() (Pranjal). - Folded in type consistency fix for fill_sg_entry() (Pranjal). drivers/dma-buf/dma-buf-mapping.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/dma-buf/dma-buf-mapping.c b/drivers/dma-buf/dma-buf-ma= pping.c index 794acff2546a..5bc769fc42ea 100644 --- a/drivers/dma-buf/dma-buf-mapping.c +++ b/drivers/dma-buf/dma-buf-mapping.c @@ -10,7 +10,7 @@ static struct scatterlist *fill_sg_entry(struct scatterli= st *sgl, size_t length, dma_addr_t addr) { unsigned int len, nents; - int i; + unsigned int i; =20 nents =3D DIV_ROUND_UP(length, UINT_MAX); for (i =3D 0; i < nents; i++) { @@ -36,7 +36,7 @@ static unsigned int calc_sg_nents(struct dma_iova_state *= state, struct phys_vec *phys_vec, size_t nr_ranges, size_t size) { - unsigned int nents =3D 0; + size_t nents =3D 0; size_t i; =20 if (!state || !dma_use_iova(state)) { @@ -51,6 +51,9 @@ static unsigned int calc_sg_nents(struct dma_iova_state *= state, nents =3D DIV_ROUND_UP(size, UINT_MAX); } =20 + if (nents > UINT_MAX) + return 0; + return nents; } =20 @@ -95,9 +98,10 @@ struct sg_table *dma_buf_phys_vec_to_sgt(struct dma_buf_= attachment *attach, size_t nr_ranges, size_t size, enum dma_data_direction dir) { - unsigned int nents, mapped_len =3D 0; struct dma_buf_dma *dma; struct scatterlist *sgl; + size_t mapped_len =3D 0; + unsigned int nents; dma_addr_t addr; size_t i; int ret; --=20 2.54.0.794.g4f17f83d09-goog